Marine propeller device



June 21, 1949. J. H. MILLER MARINE PROPELLER DEVICE Filed Jan. 15, 1946 .EEE

?atented June 21, 194%? I UNITED STATES -PATENT OFFICE MARINE PROPELLER DEVICE JosefH. Miller, Seattle, Wash.

Application January 15, 1946, Serial No. 641,244

1 Claim. 1

This invention relates to new and useful improvements and structural refinements in marine propeller devices, and applies particularly to those employed in association with outboard motors for propelling small pleasure craft, fishing boats, and other vessels of a similar nature.

The principal object of the invention is to provide a device of the character herein described, in which the propeller rotates in a Venturi-like housing, in order that the turbulence created thereby may be utilized more efiectively for the propulsion of the vessel.

A further object of the invention is to provide a device in which the propeller may be operated with appreciably higher efficiency and at considerably greater speeds without cavitation, than has heretofore been considered as practical.

Another object of the invention is to provide a device in which the propeller is protected from rocks and such, lying in shallow water, which conventionally have caused breakage of shear pins or damage to the propeller itself.

An additional object of the invention is to provide a device which is sufficiently streamlined to minimize or totally prevent the formation of eddy currents, and the construction of which includes an integral rudder.

A still further object of the invention is to provide a propeller device which is of simple construction and which may be readil disassembled for inspection or repair purposes.

With the above more important objects in view, and such other objects as may become apparent as this specification proceeds, the invention consists essentially of the arrangement and construction of parts as illustrated in the accompanying drawings, in which:

Figure l is a perspective view showing the invention as associated with an outboard motor and in situ on a boat,

Figure 2 is a central, cross-sectional view of the invention per se, and

Figure 3 is an end view of the invention, taken in the direction of the arrow 3 in Figure 2.

Like characters of reference are used to designate like parts in the specification and throughout the several views.

Referring now to the accompanying drawings in detail, the invention consists of a vertically disposed, streamlined casing l, suitably secured at the upper end thereof to an outboard motor 2, the latter being attached to the stern of a boat 3 in the conventional manner by means of the brackets 4.

The casing l is provided with a longitudinally extending bore 5 in which is journalled the motor drive shaft 6.

Formed integrally with and at the lower end of the casing I is an elongated, horizontally disposed shroud l, and a streamlined rudder fin 8 is provided integrally along the trailing edge of the casing I and along the top edge of the shroud I.

The shroud i has a forward end 9' and a rear end 9" and is provided with a Venturi-shaped passage iii, consisting 'of a forward region Ill, a rear region l0" and a connecting throat i l. The major diameter of the passage it is disposed at the forward end 9 of the shroud, from which the passage is progressively tapered throughout the length of the region Ill and is reduced to its minor diameter in the throat ii. The rear region iii" is enlarged in diameter progressively from the throat and terminates in a flared outlet opening 12 at the rear end d" of the shroud, this opening being greater than the minor diameter but smaller than the major diameter of the passage lll. It is to be observed that the passage region I0 is considerably longer than the region Mounted axially in the front portion of the passage region 9 by means of a plurality of ribs l3, I3" is a lenticular propeller carrier is, the rear end portion of which assumes the form of a rotatable hub 14 equipped with a set of propeller blades IS. The outer surface of the carrier is tapered inwardly at a greater rate than the Wall of the passage region Ill so that an annular inlet chamber IE is formed in the front portion of the passage region, which chamber is progressively increased in radial width from the forward end of the shroud. The propeller blades it are rotatable in the chamber l6 and are disposed closer to the front end of the passage than to the throat I I.

The lower end of the drive shaft 6 extends through the rib l3 into the carrier l3, and carries a small bevel gear H. The latter meshes with a similar larger gear l8 which in turn, is secured to a propeller shaft i9, journalled in the carrier. One end of the shaft l9 projects through the after end of the carrier and supports the hub l4,

Having thus described the construction of the invention the modus operandi thereof will now be presented.

When the propeller blades l5 rotate, water will be drawn into the passage l0 through the chamber l6, as indicated b the arrows 2 l The turbulence created by the propeller will be concentrated in this pasage, and as the stream proceeds in the direction of the arrows 22, the gradually decreasing diameter of the passage will impart a proportionately greater velocity to the stream, until the water reaches the restricted throat I I where its velocity will be at a maximum.

Thereafter, the stream is discharged through the progressively enlarged passage region I0 which will minimize drag and the formation of eddy currents.

While in theg foregoing there has been shown and described the preferred embodimentof this invention it is to be understood that minor changes in the details of construction, combination and arrangement of parts may be resortedeto,

without departing from the spirit and scope of the invention as claimed.

What I claim as my inventionis;

" the radialwidth of said inlet chamber is pro- In a marine propelling apparatus the com;b i H nation of a horizontally elongated shroud having forward and rear ends and provided with a Venturi-shapedpassage; said: passage having a forward relatively long region, a rear relativelylshort region. and. an intermediate .throat connecting said forward. and rear regions, .the majordiameter. of said passagebeinglat-the. forwardend of-theshroud from which the passageis inwardly tapered. throughout the length of said forward re gion and. is reduced to its minordiameter in. said throat; said rear region being..progressively enlargedl in diameten outwardly. from saidz-throat. and terminating in afiared outlet openingatthe rear end of the shroud, said.openinglbeinggreater than .the minor diameter-but smaller .thanthe major diameter of saidpassage, an elongatedlproe peller carrier mounted axiallywin thefront-.por-

tion of said forward region and projecting forwardly from the shroud, said carrier having a substantially lenticular longitudinal cross section and a rear end portion thereof consisting of a rotatable hub, the outer surface of said carrier including said hub coacting with the tapered wall of said passage to form an annular inlet chamber in the front portion of the forward passage e qgtan ase p pel er. bl des a pvi on said liub and rotatable in said inlet; chamber, said blades being disposed closer to the major diameter of said passage than to said throat, and the outer surface of said carrier including said hub being-tapered inwardly at a greater rate than the wall of the forward passage region, whereby ressively gincreased inwardly from the forward end pf said shroud.

JOSEI H. MILLER.

E ER VNQES cQHED: i The following references are of record in the file ofthis patent:

N TED; :FATENT 

